Proper illumination of vertical surfaces such as walls or other tall structures, and horizontal surfaces like walks and driveways, often requires novel lighting units and systems due to the close setback and wide spacing required. Indirect lighting units have been created to illuminate these surfaces from the setback, but units suffer from several drawbacks.
One example of an indirect lighting unit used to illuminate surfaces from a setback is the asymmetric reflector. The beam pattern created by the asymmetric reflector is intended to create a uniform illuminance on the surface by aiming the peak intensity of the beam at the furthest point to be illuminated. The remainder of the beam is utilized to fill in the target area. While these beam patterns can have high uniformity over small regions, they tend to result in spill light that extends beyond the target area. Indeed, many forward throw asymmetric fixtures have a relatively wide vertical beam angle, which results in large setback-to-throw ratios or in higher-contrast illuminance.
Existing lighting units have several other disadvantages. For example, the surface illuminated by a setback lighting unit is often brighter at the region proximal to the lighting unit and dimmer at the region distal to the lighting unit. Further, the light beam projected onto the surface is narrower at the region proximal to the lighting unit and wider at the region distal to the lighting unit, resulting in a ‘V’ pattern or scalloping effect on the surface. In order to prevent the ‘V’ pattern or scalloping effect on the surface, existing lighting systems may utilize multiple lighting units on opposing ends of the surface, or use multiple lighting units of different intensities where brighter lighting units are directed at the distal portion of the surface and weaker lighting units are directed to the proximal portion of the surface. However, multiple lighting units adds additional time and expense to a lighting system, and in many locations it is impractical or impossible to utilize multiple lighting units.
Accordingly, there is a need in the art for an improved indirect lighting unit that provides uniform illumination of a surface from a setback. For example, there is a need for narrower beam angles that provide smaller setback-to-throw ratios and higher uniformity.